This invention relates to combination locks and is more particularly concerned with front-programmable combination locks having spring-returned manual actuators.
Multiple-dial combination locks that permit a user to select a new opening combination of the lock by a programming operation at the front panel or faceplate of the lock are now well known. See, for example, U.S. Pat. Nos. 4,123,923 and 4,389,863, assigned to the assignee of the present invention. The locks of these patents have a spring-returned manual actuator that is movable relative to the faceplate and to the dials from a latching position to an unlatching position when the dials have been set to the opening combination of the lock. In another type of combination lock, disclosed in U.S. Pat. No. 3,952,561, and also assigned to the assignee of the present invention, the manual actuator and the faceplate of the lock are integral, and the faceplate and the dials form part of an assembly that moves between the latching and unlatching positions with a deadbolt action, i.e., without spring return. The integration of the faceplate and the manual actuator makes possible a combination lock that is functionally and esthetically desirable. However, in the combination lock of the last-mentioned patent, to select a new opening combination the user must manipulate a shift member that protrudes from the back cover of the lock, contrary to the recent trend toward front-programmable combination locks.